The present invention relates to a hollow golf club head, more particularly to a golf club head, at least the front part of a sole portion of which is made of metallic plate so as to adjust stiffness of the front part of the sole portion.
Hollow, metallic golf club heads have been widely used as a wood-type golf club such as a driver and a fairway wood. Generally, the hollow wood type golf club head includes a face portion for hitting a ball, a crown portion which constructs a top surface portion of the gold club head, a sole portion which constructs a bottom surface portion of the golf club head, a side portion which constructs a toe side, a back side and a heel side of the golf club head, and a hosel portion. A shaft is inserted into the hosel portion and is fixed thereto with adhesive or the like.
Although as a metal material for constructing the hollow golf club head, aluminum alloy, stainless steel, and titanium alloy have been used, in particular, titanium alloy has been widely used in recent years.
Japanese Patent Application Publication No. 2007-054200 discloses a golf club head in which the back side and the face side of the sole portion is formed with a large thickness whereas an area therebetween is formed with a small thickness. Japanese Patent Application Publication No. 2011-030836 discloses a golf club head in which the heel side of the sole portion is made with a large thickness whereas a toe side of the sole portion is made with a small thickness.